Series-Parallel LED Subsets for Fault Tolerance

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Solution Overview

Problem

Current LED technologies face inefficiencies in energy usage and fault tolerance, particularly with larger 'power chips' where series connections lead to high voltage drops and reduced system performance due to power losses in driver assemblies and resistive losses.

Innovation Solution

The development of a light emitter system with a plurality of light emitting devices interconnected on a common substrate, forming series-parallel connected subsets to achieve higher voltage operation while providing redundancy and fault tolerance, utilizing a boost power supply to optimize energy efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Power

If series connections are used to achieve higher voltage operation, then voltage output is improved, but power losses and resistive losses increase

Engineering Contradiction:
Improvevoltage outputVSAvoidpower losses
Core Design Contradiction:
PowerVSLoss of energy

Solution Approach 1:

The patent divides the light emitter into multiple independent light emitting devices (first light emitting device, second light emitting device, third light emitting device) that can be connected in series-parallel configurations. This segmentation allows the system to achieve higher voltage operation through series connections while maintaining energy efficiency by distributing the electrical load across multiple parallel subsets, thereby reducing overall resistive losses.

Inventive Principle:
Principle #1Segmentation

2Power

If series connections are used to achieve higher voltage operation, then voltage output is improved, but resistive losses increase

Engineering Contradiction:
Improvevoltage outputVSAvoidresistive losses
Core Design Contradiction:
PowerVSLoss of energy

Solution Approach 1:

The light emitter is segmented into multiple light emitting devices arranged in series-parallel subsets. By dividing the total number of devices into multiple subsets connected in series, with each subset containing devices connected in parallel, the system achieves higher voltage operation while reducing resistive losses through the parallel pathways that distribute current.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent introduces a two-dimensional electrical connection topology (series-parallel arrangement) rather than simple series or parallel connections. This dimensional change in the connection architecture allows simultaneous achievement of high voltage output and low resistive losses by operating in both series (for voltage) and parallel (for current distribution) dimensions.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

3Device complexity

If fewer chips are used to reduce device complexity, then manufacturing is simplified, but fault tolerance decreases

Engineering Contradiction:
Improvenumber of chipsVSAvoidfault tolerance
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The patent incorporates redundant light emitting devices arranged in parallel subsets before faults occur. This beforehand cushioning through redundancy ensures that if one light emitting device fails, the parallel-connected devices in the same subset can compensate, maintaining system operation and providing fault tolerance without requiring complex active protection circuits.

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

4Reliability

If more light emitting devices are interconnected to provide redundancy, then fault tolerance is improved, but device complexity increases

Engineering Contradiction:
Improvefault toleranceVSAvoidinterconnection structure
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent segments the light emitter into modular subsets of light emitting devices with standardized series-parallel interconnections. This segmentation approach provides fault tolerance through redundancy while controlling complexity by organizing devices into repeatable modular units that can be systematically interconnected using consistent connection patterns.

Inventive Principle:
Principle #1Segmentation

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This configuration enhances energy efficiency by reducing resistive losses and increases fault tolerance, allowing for higher voltage operation with fewer chips, thus improving overall system performance and yield.

Implementation Method 1

a plurality of light emitting devices which are mechanically interconnected to one another and which are electrically interconnected to provide an array of at least two serially connected subsets of light emitting devices

Methodology Applied
Scientific EffectLight emitting diode effect: Light Emitting Diode

Data Source

PatentEP2111640B1Fault tolerant light emitter and method of fabricating the same
Publication Date: 2019.05.08 WOLFSPEED INC
  • EP2111640B1 patent drawingFigure 1~3
  • EP2111640B1 patent drawingFigure 4
  • EP2111640B1 patent drawingFigure 5A~5B

AI summary

There is provided a light emitter comprising light emitting devices (for example, light emitting diodes) which are electrically interconnected to provide an array of at least two serially connected subsets of parallel connected light emitting devices, each subset comprising at least three light emitting devices. In some embodiments, the light emitting devices are from a contiguous region of a wafer. There is also provided a light emitter, comprising light emitting devices, means for mechanically interconnecting the light emitting devices and means for electrically interconnecting the light emitting devices to provide serially connected subsets interconnected in parallel, each subset comprising at least three light emitting devices. Also, methods of fabricating light emitters.